[inflation]

From: http://www.icsalabs.com/html/communities/WLAN/wp_ssid_hiding.pdf

This presence in management messages, or frames, is an oft-overlooked detail of the IEEE 802.11 specification that is critical to debunking the myth of SSID hiding. Management messages are always sent in the clear, even when link encryption (WEP or WPA) is used, so the SSID is visible to anyone who can intercept these frames.

[e_castillo]

When SSID is turned off it's "really" not off just not sent until needed... So someone wanting a passphrase, MAC and even SSID would need to "hang" around in range of an AP and use Airsnort or some other sniffing util to get what they needed.